Upper Body/ Core Strength and Running Performance
Does upper body/ core strength really make a difference?
Runners are known for having incredibly weak upper bodies, but can this impact performance?
Power Leaks
Running is almost exclusively thought of as a lower body sport, while your upper body is rarely a topic of discussion. In reality, your upper body (and specifically your core) is an incredibly important part of your body, involved with transfer of force. When you have weak muscles in your upper body, your running economy can be negatively affected due to power leaks.
Essentially, power leaks are wasted energy from excess movement. A common place for power leaks to occur is around your shoulder joint. This is typically a result of an inability to stabilize muscles around that shoulder (due to weakness). In an ideal world, your shoulder joint should work to pull your arm back as the leg on the same side steps forward. However, weakness around the shoulder joint can result in excessive rotation and/or a limited and crooked arm swing.
When your arms swing in any other motion other than forward/ back (i.e a crossing motion), you throw yourself off balance and your lower body/core have to work extra hard to stay upright. This increase in lower body work results in a decrease in running economy. In addition, an uncontrolled arm swing can also be a significant risk factor for lower limb injuries if your lower body/ core is not strong enough to counterbalance the motion from your arms.
Redefining Your Core
Generally, it is assumed that your core is contained to the muscles around your abdomen. However in reality, your core is the section of your body from your shoulder joint to your hip joint. The main purpose of this section of your body is to transfer from your your lower body to upper body and act as a base of support for your limbs.
You can image your core like the legs of a bench during a bench press exercise. You can push much more weight if your bench is on a flat, stable surface, compared to if that same bench were on wheels. If your bench was on wheels, every time you pushed up - part of your power would be lost when the bench moved. Similarly, when you generate force through your arms and legs, part of that power is lost if your core lacks the strength to stay stable.
Power Leaks in your Core
Just as we can have power leaks in our upper body, our core is susceptible to power leaks (excessive movement) if it is not well trained. However the result of excessive movement though your core is not only “wasted energy” - it also inhibits your arms and legs from producing power.
How does your core affect your arms and legs?
As your foot touches the ground, you flex your hip, knee and ankle to absorb that force, then extend each of those joints to push yourself forward. This creates a rotational force with each step. In order to counterbalance this rotational force, your arm and shoulder joint must act in the opposite direction (i.e. as your right leg pushes you forward, your right arm/ shoulder pull you back). If you have a weak core, your shoulder doesn’t have a strong base of support to pull your arm back (like the bench press on wheels). That lack of shoulder movement affects your ability to counteract the rotational force your leg creates. When this happens, only part of that force generated by your leg will be used to push you forward, and the rest will be lost.
Core, Balance and Trail Running
Not only does a weak core affect your ability to transfer force and decrease your power output, but it also affects your balance. Essentially, running is just a series of single leg jumps, balancing and jumping from leg to leg. If you have a weak core, you have an unstable base of support and this affects the power of your jumps and balance on landing. If you are a trail runner, this lack of balance has huge implications for both your performance and risk of injury,
Trail races often require runners to jump over streams or fallen branches and exposed roots. To successfully make your jump, you need both a strong take-off and landing. Limited power in your take off (due to a weak core) can result in your jump coming up short and landing on the root or in the stream (where you might not know what you are landing on). Even if you manage to stick your landing, a weak core will likely rob you of your balance upon landing and cost you time to regain it before you can continue running. However, a store core (in addition to plyometric training) will give you more power in your take-off and a smooth landing so that your running stride isn’t interrupted through the obstacles.
Training The Upper Body
Although it many seem insignificant, our upper body does play a role in transfer of force and power production. This doesn’t necessarily mean that upper and lower body strength should get equal attention, but rather the upper body should stop getting ignored. Using bands (i.e. pull aparts) can be a great way to start to build strength and stability within the muscles around your shoulder joint. One great advantage to doing band-based exercises is that most of them can be done at home with little to no equipment (besides the band). Banded pull-aparts in addition to a glute activation exercise (i.e. monster walks) would be 2 great exercises to pair together before your run. Neither of these exercises are particularly fatiguing, but can help activate and warm up some of the muscles you should be using when you run.
Be sure to keep in mind that all your muscles are interconnected, and therefore your whole body should be considered when performing any exercise. For example – if you are doing a shoulder dominated exercise – what does your lower back look like? Are your glutes engaged? Further, what does your posture look like when performing a monster walk? Although one particular muscle group is dominating an exercise – it doesn’t mean that other muscle groups can’t be active.
Final Take-Aways
The muscles of your body are much more interconnected than what the anatomy books show. Instead of one muscle stopping and a new one beginning, your muscles flow into one another and work together as one big machine, as opposed to individual parts. To optimize our machine as a whole, each part needs to be strong. This means that although our legs seems like the only important muscle when you run, all muscles of our body play an important role (and have the potential to negatively affect your run)
MSc. Strength and Conditioning, C.S.C.S
Functional Range Conditioning Specialist
Runner/ Triathlete
